Oil Leak

[nobull1]

On my 763 I had a pump leaking at the seal which required the motor to come out. We removed the motor replaced the seal and all seemed fine. After using the machine for a few hours and leaving it outside in the rain I found I had an oil leak by the cover for the chain case/fuel plugs. Previously I had spot welded the plate in place as the holes were stripped. It isn't impossible to get off just a pain. It appears that it might be residual oil under the fuel tank. What I don't know is how much oil it might hold as I never had a tank out before and it has leaked a fair amount so far. The oil only really appears after a heavy rain so I don't think it is the chain case plug or it would leak all the time. The colour is slightly dirty but not black. I have cleaned all around the tank, lines and hoses and all appears dry. If it is not residual oil than I guess it must be leaking from the chain case somewhere? The rear top chain case cover is is tight and not leaking and all appears dry. I wonder if there is a vent somewhere between the tank and chain case? Any ideas welcome.
Brian

 

[Tazza]

You know about the plug on the rear of the chain case where you can also drain the fuel tank? There is also a breather plug on the rear inspection plate of the chain case near the pumps. If you can. i'd remove the cover under the fuel tank and chain case and give it a clean and see if you get any more oil. These plugs are just rubber with a steel insert.
The oil is down low or is it up high like on top of the chain case? Hopefully its just oil from pulling the pump/motor out. Oil leaks drive me crazy too.....

 

[nobull1]

You know about the plug on the rear of the chain case where you can also drain the fuel tank? There is also a breather plug on the rear inspection plate of the chain case near the pumps. If you can. i'd remove the cover under the fuel tank and chain case and give it a clean and see if you get any more oil. These plugs are just rubber with a steel insert.
The oil is down low or is it up high like on top of the chain case? Hopefully its just oil from pulling the pump/motor out. Oil leaks drive me crazy too.....

I am going to grind off the weld on the cover today and see if i can tell where the oil is coming from. If it isn't obvious I will take the pressure washer to the whole area between the tanks and then see what happens. My thought is that if it was the drain plug it should be leaking all the time as there is no restriction to the oil just running out. Now I am thinking it might be dirt packed so far up the sides of the tank between the chain case and fuel tank that it is working as a dam and when it rains the oil comes to the top and runs out. I would be happy with this because eventually it would just stop. But at the present time it doesn't "appear" to be slowing down. The other thought is somehow the chain case is leaking somewhere other than the drain plug. Although unlikely due to the thickness of the metal and hopefully not, it is possible. Hopefully I will know more later today. I will also try to fix the cover problem by tapping the holes or welding a bolt in the hole so I can put a nut on the outside of the cover.
Brian

 

[skidsteer.ca]

I am going to grind off the weld on the cover today and see if i can tell where the oil is coming from. If it isn't obvious I will take the pressure washer to the whole area between the tanks and then see what happens. My thought is that if it was the drain plug it should be leaking all the time as there is no restriction to the oil just running out. Now I am thinking it might be dirt packed so far up the sides of the tank between the chain case and fuel tank that it is working as a dam and when it rains the oil comes to the top and runs out. I would be happy with this because eventually it would just stop. But at the present time it doesn't "appear" to be slowing down. The other thought is somehow the chain case is leaking somewhere other than the drain plug. Although unlikely due to the thickness of the metal and hopefully not, it is possible. Hopefully I will know more later today. I will also try to fix the cover problem by tapping the holes or welding a bolt in the hole so I can put a nut on the outside of the cover.
Brian

Brian
Careful welding down there with the plastic fuel tank. On my 753 I ended up tapping those 3 holes to 7/16 nc. Can U pressure wash around the sides of the fuel tank as much as possible, maybe you can flush the "dam" around the side of the tank free and get it to drain out the bottom.
Ken

 

[nobull1]

Brian
Careful welding down there with the plastic fuel tank. On my 753 I ended up tapping those 3 holes to 7/16 nc. Can U pressure wash around the sides of the fuel tank as much as possible, maybe you can flush the "dam" around the side of the tank free and get it to drain out the bottom.
Ken

Well I ground the weld off the inspection plate. Once I had the plate removed I stuck the pressure washer in from the top and bottom and blasted everything I could get at. I probably got a cup of oil soaked sand/grease mixture. Then I went with a piece of coat hanger and cleaned between the the fuel tank and steel base. Now I feel pretty confident that it is not the drain plug leaking because after a couple of hours there was no oil around the plug. As to what it is I guess I will have to use it and see if it leaks before or after it rains, or both. At least now I should be able to get a better idea where it is coming from. I also stuck a couple of bolts down from the top through the stripped holes and welded them in place from the bottom so I can just thread and locktite nuts on to hold the cover . The holes were already past 7/16 and would have had to go to 1/2", so I took the easy way out. Now it will take 30 seconds to remove the inspection cover instead of a half hour.

 

[nobull1]

Well I ground the weld off the inspection plate. Once I had the plate removed I stuck the pressure washer in from the top and bottom and blasted everything I could get at. I probably got a cup of oil soaked sand/grease mixture. Then I went with a piece of coat hanger and cleaned between the the fuel tank and steel base. Now I feel pretty confident that it is not the drain plug leaking because after a couple of hours there was no oil around the plug. As to what it is I guess I will have to use it and see if it leaks before or after it rains, or both. At least now I should be able to get a better idea where it is coming from. I also stuck a couple of bolts down from the top through the stripped holes and welded them in place from the bottom so I can just thread and locktite nuts on to hold the cover . The holes were already past 7/16 and would have had to go to 1/2", so I took the easy way out. Now it will take 30 seconds to remove the inspection cover instead of a half hour.

I have been monitoring the oil leak to see where it is coming from. It appears it is coming from the gas tank side as it is making drops at the bottom of the fuel tank rubber plug. On the chain case side it is bone dry so probably not coming from that area. I suspect it is just residual oil leaking between the tank and skid shield through the gunk that is still there. Time will tell for sure.

 

[Tazza]

I have been monitoring the oil leak to see where it is coming from. It appears it is coming from the gas tank side as it is making drops at the bottom of the fuel tank rubber plug. On the chain case side it is bone dry so probably not coming from that area. I suspect it is just residual oil leaking between the tank and skid shield through the gunk that is still there. Time will tell for sure.

Hopefully that is all it is, there is a lot of surface area under there for oil to pool up and slowly leak out. The only thing you can check is the hoses from the oil cooler and oil filter. Even the high pressure hose from the hydraulic pump to see if its wet, everything else is on the chain case side of the chassis and shouldn't drop around the fuel tank. From memory the pump doesn't even sit over the fuel tank....
I really know how anoying small leaks are, i have one on a 751 that is going to be a pain to fix!

 

[nobull1]

Hopefully that is all it is, there is a lot of surface area under there for oil to pool up and slowly leak out. The only thing you can check is the hoses from the oil cooler and oil filter. Even the high pressure hose from the hydraulic pump to see if its wet, everything else is on the chain case side of the chassis and shouldn't drop around the fuel tank. From memory the pump doesn't even sit over the fuel tank....
I really know how anoying small leaks are, i have one on a 751 that is going to be a pain to fix!

The oil leak went away after a couple of months. I suspect it was from residual oil from the leaking/gunk and motor removal. Every time it rained or the machine was tipped forward quite a bit it would leak. I was sure it was a leak but eventually it went away on it's own.

 

[Tazza]

The oil leak went away after a couple of months. I suspect it was from residual oil from the leaking/gunk and motor removal. Every time it rained or the machine was tipped forward quite a bit it would leak. I was sure it was a leak but eventually it went away on it's own.

Yeah, the oil can sit around for some time! even a small leak won't show up then there is a spot on the floor. Fix the leak and its STILL there, but its the oil between the frame and the oil tank. Even a heap of de-greaser never seems to get it all....